A review of the feasibility of producing processed cheese using non-enzymatic direct acidification procedures M. Ashraf Pal Division of Animal Products Technology, Faculty of Veterinary Sciences and Animal Husbandry, S.K University of Agricultural Sciences and Technology, Srinagar, Kashmir, India (Received 8 August 2000; Accepted in revised form 10 May 2001) Summary This review covers various aspects of studies, which were done to develop processes to make products that resemble traditional/processed cheese without the use of micro- organisms or enzyme system. Several manufacturing techniques and incorporation of various ingredients/additives, examples of which are emulsifying salts, texture modifiers and flavour enhancers, in the formulations are discussed. Characteristics like rheology, chemical composition, biochemical changes and microstructure of such products are also given. Keywords Biochemical changes, chemical composition, ingredients/additives, manufacture, microstructure. Introduction Processed cheese, since its inception, has been produced using either hard cheese varieties like cheddar of varying maturity or blends of cheese of different ages depending upon the requirements of the formulation selected by the manufacturer. When the traditional methods of cheese produc- tion are studied, however, the fermentation and rennet addition processes prove to be a stumbling block to complete mechanization of the cheese production besides adding significantly to the cost of production. It is, of course, also worth consider- ing whether mechanization of these processes is needed or some other approach would be advan- tageous. Therefore, it seems plausible to examine the development of processes for producing prod- ucts resembling traditional cheese/processed cheese without the use of micro-organisms or enzyme systems. There has been a start in the direction towards producing processed cheese using directly acidified, nonrenneted cheeses and the work conducted so far is detailed below: Manufacture Investigations on the feasibility of producing processed cheese using nonrennet direct acidifica- tion procedures were reported by Rosenau et al. (1975). The steps involved consisted of using 30- gallon (c.135 L) batches of homogenized milk (2% fat), heating to 88 °C and cooling with 1 N HCl which was added simultaneously until a pH of 4.4 was achieved. The temperature at this stage was 20 °C. The curds were collected and pressed overnight at a pressure of 3.4 bar in cheese hoops. Sufficient time (c. 1 h) was allowed for the curd to equilibrate with the whey in order to get the curds easily pressed to the desired moisture level. The pressed cake was comminuted and 2 kg portions mixed at a temperature of 70 °C. Sufficient 10 N NaOH was added to raise the pH into the range of 7–9 followed by lowering the pH to 5.2 using 80% lactic acid. The mass was poured into processed cheese cartons and refrigerated. The product has been claimed to possess textural properties mid- way between medium and processed cheddar with appreciably lower cost of production compared with commercial cheddar. In another study, Rosenau et al. (1978) modified his previous tech- nique by incorporating certain texturizing agents to improve upon certain rheological characteristics Correspondent: Fax: 0194-62207; e-mail: palma@indiatimes.com International Journal of Food Science and Technology 2002, 37, 229–237 229 Ó 2002 Blackwell Science Ltd